I agree that having to root the phone, and manufacturers making their builds public is an issue. Mozilla can't quite control this, as they can't legally redistribute proprietary and closed source binary blobs that are the hardware drivers. But I've brought it up numerous times to the legal dept that the requirements for both should be part of the branding requirements.
Rooting is a PITA, granted, but you shouldn't be afraid of compiling from source, ever, especially if you're reading "hacker" news.